RACISIM! (added to the story only for the sake of showing how horrible it is to have in your soicety) [Trigger Warning: racist words and views may be mentioned in passing]

So... how do you think it's best to add this to a fictional society? What makes fictional racisim beleivable, comparable and present in a society (like the Death Eaters in Harry Potter), not beaten your reader over the head and fumble the message (like Mankind Divided nonsesical 'Aug Lives Matter') or feel like it was accidently let in when nobody was looking (like how occassionaly it feels like race determines character in Tolkien books (even though it's so far off from the rest of the messages of his stories, Narrative Dissonance doesn't even begin to cover it). Do you make people with racist beleifs as stupid as their ideaology, make them as scarry as their beleifs, or have it sneak its way into otherwise sypathetic characters? Let's just focus on the general mechanics of the phenomenon instead of the thing itself... but regardless... [Trigger Warning: racist words and views may be mentioned in passing]